Grade 9 Biology (1)

7/27/2019 Grade 9 Biology (1)

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3/9/2013

Breathing

- It is exchange of gases inside lungs

- It is the inhalation and exhalation of air.

Aerobic respiration

- It is the burning of food with oxygen to produce energy.

Anaerobic respiration

- It the producing of energy from food in absence of oxygen.

Human Respiratory system

It consists of :

Nose:

1. It has hair to trap dust.

2. It has mucus to moist air

3. It has blood capillaries to warm air

- Nose is the safety valve of your respiratory system. Why?

Pharynx

It is the common passage of air and food.

Larynx

It is a voice organ

It has epiglottis to close it when you swallow food or drink water.

Trachea and bronchi

It allows air to pass from larynx to lungs

It consists of cartilaginous rings to keep it open all the time.

It is lined with cilia that make flicking in one way to move mucus outside trachea.

Lungs

They consist of alveoli which covered with very thin blood capillaries

Exchange of gases takes place through the wall of alveoli

Lungs have spongy appearance because they consist of tiny air sacs called alveoli



Lungs have pink colour because the alveoli covered with tiny blood capillaries

Diaphragm

It is a thin muscular sheet that separate between thorax and abdomen

It helps in respiration mechanism

Pleural membrane

It surrounds pleural cavity that contain fluid around lungs to protect them from friction with chest

Intercostal muscles and ribs

They surround and protect lungs

They help in respiration mechanism

H.W

With a fully labelled diagram show the structure of human respiratory system with the function of each part.



8/9/2013

Inhaling - Exhaling

Inhaling Exhaling

1. It is the act of breathing In Out

2. .........intercostal muscle contract External Internal

3. Ribs move Upward Downward

4. Diaphragm Contracts Relaxes5. Diaphragm moves Downwards upwards

6. Volume of chest Increases Decreases

7. Volume of lungs Increases Decreases

8. Air pressure in lungs Decreases Increases

9. Air is Inhaled in Exhaled out

What is meant by?

1. Ventilation

It is the movement of air inside and outside lungs

2. Respiration rate

It is the number of breathing per unit time

3. Tidal volume

The volume of air which enters and comes out from lungs at rest

4. Residual volume

The volume of air which can't be exhaled out inside the lung

5. Vital capacity

It is the maximum volume of air which can be exhaled out or inhaled in hard exercises.

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10/9/2013

Quiz

Define:

1. Vital capacity

2. Breathing rate

3. Internal respiration

Compare between inhaling and exhaling processes



15/9/2013

Smoking

Harmful substances

Carbon monoxide

It is produced due to incomplete combustion of chemicals in cigarette

Red blood cells have greater affinity to combine with carbon monoxide than oxygen

So smokers suffer from short breathing with high rate to compensate the shortage of oxygen in blood

Tar

It causes the paralysis of ciliaIt has carcinogenic effect

Nicotine

It increases the blood pressure

It increases the ability of blood to coagulate inside arteries and veins causing thrombus or stroke

It causes addiction

Emphysema

It causes the destroying of alveoli because smoking make alveoli wall thinner so coughing cause its destruction so the

surface area of exchange gases is decreased

Bronchitis

Accumulation of mucus in trachea act as a very good culture for bacteria to survive causing inflammation in lungs

Tuberculosis

The smokers are exposed to infection with bacteria that cause this disease because the immune system of smokers

becomes weak.

Lung cancer

Cancer means the cells lose their ability to control cell division so they divide continuously forming tumor, this tumor wil

make function as some endocrine glands cause disturbance in the body

Tar induces cancer

There is a correlation between lung cancer and smoker not causation

Because all infected persons with lung cancer were smokers but not all smokers have lung cancer.

Short term effect of smoking

1. Rise in blood pressure

2. Coughing

Long term effect1. Emphysema

2. Lung cancer

3. Bronchitis

H.W Book page 123, 126, 127 and 129



17/9/2013

Page 127

Pumping exhaled air in lungs increase the concentration of carbon dioxide in blood that act as signal for brain to speed

up the breathing mechanism and return its activity again.

Tidal volume 500 cm3

in one inhale, in one minute, 16 x500 = 8 liters

Vital capacity 3.5 litre in one inhale, in one minute, 20X3.5 = 70 liters

Similarities

1. Both of them have very large surface area

2. Both wall of them made of one cell thick

3. Both of them have very rich blood capillaries



Quiz

Mention the function of:

1. Lungs

2. Diaphragm

Mention the harmful chemicals formed on burning cigarette with the harmful of each one on your healthy condition.kl



24/9/2013

ExcretionIt is the getting rid of waste products outside the body in the form of:

Urine through urinary system

Sweat through skin

Exhaled air contains CO2 through lungs.Excretory substances

Urea

Uric acid

Excess salts

Water

Excretory organs

Skin -------------------excrete sweat

Liver ------------------forms urea

Kidneys----------------excrete urine

Lungs------------excrete exhaled air which contains carbon dioxide and water vapour





and the kidneys

- What is meant by each of the followings?

1. Excretion2. Ultrafiltration3. Selective reabsorption

4. Osmoregulation

5. Homeostasis

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Grade 9 Biology (1)